Shubo: The yeast starter
determines the flavor and aromas of the sake.

At our brewery we have equipment that allows us to take the
yeast from a particularly good batch of sake and save it, cultivating
and reconstituting it later.

Naturally we do use different strains of yeast. But making sure
these do not get mixed is a big part of controlling the yeast
starter and moromi that calls for great effort.

"Yama-oroshi
Haishi" yeast starter

The main method of
brewing sake today uses a step called "sokujo moto,"
or "fast-brewed moto," in which lactic acid is added
at the beginning.
There is however another, much more labor intensive method that
takes about am month to prepare, known as "yamahai."

Our toji revived the use of yamahai brewing methods at our brewery,
which brings out a settled acidity in the flavor. This is very
much enjoyed by sake afficionados.

Big
bubbles in a tank of fermenting sake

During fermentation,
the mash will bubble up quite a bit. There are names for each
of the various appearances the foam will take as fermentation
progresses. "Rock foam," "high foam," and
"falling foam" are a few of these, with the final
being "big bubbles." From long ago toji have said
that the bigger these big bubbles, the better the sake will
be. At our brewery, our brewers can often see bubbles as large
as 40 centimeters.